1. Field
Embodiments relate generally to a method for finishing and strengthening edges of articles made of brittle materials.
2. Technical Background
Mechanical separation is an example of a method for cutting a glass sheet. Mechanical separation typically involves mechanically scoring a glass sheet to form a score line in the glass sheet and subsequently breaking the glass sheet along the score line. The mechanical scoring and breaking result in a glass sheet with a rough/sharp edge, which are are undesirable and makes the glass sheet vulnerable to cracking. Material can be removed from the rough/sharp edge in order to smoothen/dull the edge and reduce the glass sheet's vulnerability to cracking. Abrasive grinding can be used to mechanically remove material from the rough/sharp edge of the glass sheet. Abrasive grinding involves use of a metal grinding tool with micron-sized abrasive particles which may or may not be fixed on the tool to remove material. The mechanism of material removal using abrasive grinding is considered to involve fracturing. As a result, fracture sites can appear on the edge after grinding. The larger the abrasive particles used in the grinding, the larger the fracture sites that can appear on the edge after grinding. These fracture sites effectively become stress concentrations and fracture initiation sites, which result in a finished glass sheet having a lower edge strength than the initial glass sheet. Grinding tools with smaller abrasive particles and/or mechanical polishing tools can be used to reduce the size of the fracture sites. Mechanical polishing tools can be metal or polymer wheels. Mechanical polishing also involves use of abrasive particles, but the abrasive particles are not fixed on the polishing tool. A rough edge may be avoided by cutting the glass sheet by laser separation. However, a glass sheet that is cut by laser separation is typically not exempt from a sharp edge. Laser scoring produces sharp edges and corners that are highly susceptible to impact damage, therefore it is desirable to further shape finish laser scored edges. Typically, a polishing wheel made of a series of hard bound abrasives and/or a lap with loose slurry may be used to remove the sharp laser scored edge, e.g., by beveling or rounding the edge. Several polishing steps are typically needed to remove the sharp edge, which can significantly increase the cost of the finished glass sheet.